Biochemistry 3382A Lecture Notes - Lecture 5: Plasmid, Conformational Change, Chromosome

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11 Jan 2015

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The origin of replication is a specific site(s) at which unwinding and copying begins. In e. coli, one origin of replication exists, however in humans, lots (thousands) of them exist. Initiation of dna replication is what controls the process. Once replication begins it will continue to the end or cell is going to die. It is an irreversible reaction once begun and is regulated by many factors. The rate of this reaction is not adjustable and it is known that in e. coli the rate is. 700 nt/sec while in eukaryotes it is 50 nt/sec. All the dna replicated from a single origin is a replicon. So for e. coli, the replicon is the entire chromosome. For humans, there is a replicon every 40 or 50 bases or so. The replicator is a set of dna sequences that is sufficient for replication.

Related Questions

1. In Humans, many types of cancers have been linked to?

A. Duplications
B. Inversions
C. translocations
D. deletions
E all of these

2. 5- bromoouracil is mutagenic because it is a(n)

a. base-modifying agent
b. base analog
c. intercalating agent
d. alkylating agent.

3.Ultraviolet radiation creates __________ in DNA

A. 5-methyl cytosine residues
B. breakages
C point mutations
D. mutational hot spots
E thymine dimers

4. The telomeres of chromosomes is composed of

A. heterochromatin
b. nucleosome
c. histone
d. achromatic

5. In eukaryotes, a replicon is

a. the distance between the origin of replication and thetermination of replication
b. a single chromosome
c. the entire genome
d. one DNA strand of a single chromosome

6. In a nonreciprocal interchomosomal translocation, a segment of achromosome is

a. exchanged with an identical segment on a differentchromosome
b. exchanged with an identical segment on a sister chromatid
c. transferred to a different chromosome without a reciprocalexchange of genetic material
d. transferred to a new location on the same chromosome without areciprocal exchange of genetic material

7. Somatic mutations are always.

a. spontaneous
b. carcinogenic
c. heritable
d. lethal
e. none of these

8. A woman with an XO genotype is

a. aneuploid
b. euploid
c. diploid
d. poluploid

9. Spontaneous mutations may occur as a result of

a. all of these
b. errors in DNA replication
c. transposition
d. none of these
e. normal cell biochemistry

10. In the semi conservative model of DNA replication, progenydouble helices consist of

a. one parental DNA strand and one new strand
b. one parental DNA strand and one new RNA strand
c. two new RNA strands
d. two parental DNA strands
e. two new DNA strands

11. A mutation in a gene may alter a cellâs

a. phenotype
b. genotype and phenotype
c. genotype

12. During replication, the direction of synthesis of new DNA fromthe leading strand is

a. both 5â to 3â and 3â to 5â
b. none of these
c. 3â to 5â
d. from left to right only
e. 5â to 3â only

13. A mutation that results in a switch from a purine-pyramidingbase pair to a pyramiding-purine base pair is a _________mutation.

a. neutral
b. transition
c. missense
d. transversion
e. nonsense

14. A trisomic human cell would contain how many chromosomes?

a. 45
b. 46,
c. 47.
d. 48

15. In a strand of DNA, a _____________ bond connects the phosphategroup of one nucleotide to the sugar of the adjacentnucleotide

a. hydrogen
b. ester
c. phosphodiester
d. phosphate
e. disulfide

16. Cri-du-chat syndrome is caused by which type of chromosomalmutation?

a. deletion
b. duplication
c. translocation
d. transversion
e. inversion

17. During replication, the role of DNA primase is to

a. add nucleotide to the growing DNA chain
b. synthesize a short chain for RNA
c. untwist the double helix at the origin of replication
d. relax the super coiling of the double helix
e. synthesize the primo some

18. A(n) ____________ inversion involves the Centro mere

a. chromocentric
b. paracentric
c. epicentric
d. percentric
e. concentric

19. Which of the following substances mutates DNA by intercalatingbetween adjacent base pairs?

a. methyl methane sulfonate
b. all of these
c. nitrous acid
d. 2-amino urine
e. acridine orange

20. A molecule of RNA is always

a. double stranded
b. helical
c. nonparallel
d. all of these
e. none of these

21. Mutagenesis of cells using radiation or a chemicalintercalating agent could be used to create __________ mutations ina region of DNA.

a. random
b. both random and site-specific
c. site-specific

22. In Griffithsâs tranformation experiments, the mice died whenthey were injected with

a. living, no virulent bacteria
b. living, virulent bacteria
c. heat-killed, no virulent bacteria
d. living, nonvirulent bacteria
e. both B and D

23. A monoploid human cells

a. shows only the excessive phenotype of all these genes
b. would be functionally impaired
c. is normal
d. would not survive

24. Gametes containing an abnormal number of chromosomes may occuras a result of

a. paracentric inversion
b. reciprocal translocation
c. disjunction of chromosomes
d. unequal crossing over

25. DNA may be altered as a result of _____________ events thatoccur normally in cells

a. depurination
b. deamination
c. depyrimidation
d. all of the above
e. none of the above

26. Which enzyme prevents DNA from tangling up as the replicationfork migrates during replication?

a. DNA polymerase I
b. DNA helicase
c. topoisonmerase
d. DNA polymerase III
e. DNA gyrase

27. Which of the following enzymes play an important role in DNAreplication?

a. DNA helicase
b. DNA ligase
c. DNA primase
d. all of them
e. DNA polymerase III

28. A mutation gene sustains a mutation that restores the originalphenotype, This is a

a. frame shift mutation
b. transversion
c. reversion
d. transition
e. forward mutation

29. A dicentric chromosome has two

a. telomeres
b. mutations
c. arms
d. centromeres

30. Which type of chromosomal mutation cannot revert to thewild-type state

a. duplication
b. deletion
c. translocation
d. both A and C
e. all of them

31. Translation of histone mRNAs occurs during which phase of theeukaryotic cell cycle?

a. M
b. G1
c. G2
d. S
e. all of these

32. After removal of the RNA primers, Okazaki fragments are joinedthrough a reaction that involves which enzyme?

a. RNA polymerase
b. DNA helicase
c. DNA polymerase
d. DNA primase
e. DNA ligase

33. Which of the following is required for the synthesis of DNAduring replication?

a. DNA polymerase
b. magnesium ions
c. all of them
d. template DNA
e. dNTPs

34. Most of the genome of an active cell consists of

a. heterochromatin
b. histochromatin
c. poluchromatin
d. euchromatin

35. In eukaryotes, DNA replication begins,

a. a single origin of replication on each chromosome
b. a single origin of replication on each chromosome
c. multiple origins of replication on each chromosome
d. all of the above
e. none of the above

36. A human cell contains 2 sets of 24 chromosomes is

a. euploid
b. haploid
c. polyploid
d. aneuploid

37. Pseudodominance occurs as a result of which type ofmutation?

a. translocation
b. duppolication
c. all of these
d. point mutation
e. deletion

38. The enzymatic activity of a telomerase is best described asa

a. none of these
b. polymerase
c. ligase
d. reverse transcriptase
e. topoisomerase

39. A Barr body is an example of

a. constitutive heterochromatin
b. facultative heterochromatin
c. facultative euchromatin
d. constitutive euchromatin

40. An addition or deletion of one or two base pairs in a genecauses a ____________ mutation

a. Transition
b. frameshift
c. nonsense
d. transversion
e. neutral

41. A heterozygous chromosomal inversion can be detected

a. by cytogenetic observation of loops in chromosomes
b. through genetic studies indicating a decrease in the frequencyof recombination between genes
c. by observing a decrease in the number of viable progenyfollowing genetic crosses
d. all of the above

42. The mutagen 5-bromouracil is an analog of which base?

a. adenine
b. threonine
c. thymine
d. cystosine
e. uracil

43. A mutation that changes a codon from one that represents anamino acid to one that signals a chain termination is a______________ mutation.

a. neutral
b. missense
c. frame shift
d. nonsense

44. A chromosomal mutation that results in an increase in theamount of DNA is a(n)

a. duplication
b. inversion
c. deletion
d. both A and C
e. all of the above

45. Prior to replication, the DNA double helix must be untwisted bywhich type of enzyme?

a. topoisomerase
b. ligase
c. polymerase
d. helicase
e. primase

46. In his transformation experiments, Griffiths used cultures ofwhich bacterium?

a. Sacchromyces cerevisiae
b. Escherichia coli
c. Streptococcus pneumoniae.
d. Bacillus cereus
e. Eneterococcus faecalis

47. A mutation changes a codon from a UCG to a UAG. This is a____________ mutation?

a. point
b. nonsense
c. silent
d. both A and B
e. all of the above

48. In eukaryotes, DNA replication

a. is initiated at several sites on chromosomes
b. occurs bidirectional
c. is semidiscontinuous
d. all of the above
e. none of the above

49. Which of the following bacteria are used in the Amestest?

a. Pseudomonas aeruginosa
b. Escherichia coli
c. Vibrio cholera
d. Salmonella typhimurium
e. Rickettsia rickettsii

50. Which of the following changes represents a missensemutation?

a. UGA (stop) to UAG (stop)
b. AAA (lysine) to AGA (arginine)
c. UUU (phenylalanine) to UAA (stop)
d. AUG (methionine) to UGA (stop)
e. AAA (lysine) to AAG (lysine)

You decide to identify the CFTR mutation by analyzing the genomic DNA of your patients compared to healthy individuals. You specifically are looking to see whether a specific 3' gene truncation has occurred in the patients. You will determine this using hybridization techniques with samples from healthy and CF patients. Which of the following will allow you to accomplish this?

	Using an RNA probe complementary to the region not removed by the truncation.
	Using an RNA probe complementary to the region removed by the truncation.
	Using an DNA probe complementary to the region not removed by the truncation.
	Using an DNA probe complementary to the region removed by the truncation.

To conduct the hybridization experiment, you are trying to decide between using a DNA or RNA probe. Which would be ideal to use and why?

	As both are composed of nucleic acids, using either would result in identical results.
	An RNA probe because RNA has uracil bases.
	An RNA probe because it could also be used in a translation experiment.
	A DNA probe because it is more stable than RNA.
	A DNA probe because RNA cannot bind to DNA.

Imagine Hershey/Chase had used an RNA virus (genome composed of RNA) instead of a DNA virus in their experiment. Would radioactivity still have been found in the pellet?

	No, because only DNA can be labeled with radioactivity.
	No, because the RNA genome would not enter the bacteria upon infection.
	No, because while DNA and RNA nucleotides are similar, they are not identical.
	Yes, because DNA and RNA nucleotides are similar.
	Yes, because genome in any form (DNA, RNA, protein) would be labeled similarly.

The human genome consists mostly of non-coding DNA. Which of the following are benefits of this?

	Random DNA mutations generally won't affect RNA and protein function.
	It is faster to duplicate the genome when these are present.
	The existence of introns can lead to multiple variations of proteins encoded by a single gene.
	It is unlikely transposons would exist in the genome if there was too much protein coding DNA.

You accidentally add a mutant dNTP (which has an H instead of an OH connected to the 3â carbon) to a reaction where DNA is being replicated. Which of the following is true of this mutant dNTP?

	It can be incorporated into DNA strand but cannot form a phosphodiester bond with an incoming wild type dNTP
	It can be incorporated into a DNA strand but cannot base pair with a complementary nucleotide
	It can be incorporated into a DNA strand and can form a phosphodiester bond with an incoming dNTP, but only if it is another mutant dNTP
	It cannot be incorporated into a DNA strand.

Andrew Murray's sister, Andrea, is adding to her brother's work on chromosomes. She is using cells that are unable to synthesize adenine (âade) and histidine (âhis). The plasmid she is currently working with consists of an origin of replication and the Ade gene.

Following her transformation of the plasmid into her yeast, what media will the cells be plated on to select for cells that have picked up the plasmid?

	Media containing histidine
	Media containing adenine
	Media lacking adenine
	Media lacking histidine

She starts by attempting to add the centromere DNA into a plasmid containing the origin of replication. Unfortunately, when adding the centromere sequence, the origin of replication is removed, thus leaving a plasmid with only a centromere and selection marker. Following plasmid transformation, what growth result will she see on her plates?

	No colonies
	Little colonies
	Big colonies

She fixes the mistakes from the previous experiment and now has a complete plasmid (selection marker, origin of replication, centromere). She then inserts telomere sequences into the plasmid. How will this impact her transformation?

	It will not impact her transformation
	Her transformation will no longer work because plasmids donât require telomeres
	She will now see much larger colonies
	She will now see fewer but larger colonies
	She will now see smaller colonies

In the Meselson/Stahl experiment, E. coli were first grown in media containing heavy nitrogen, 15N, and then transferred to light nitrogen, 14N, at the beginning of the experiment.

Imagine that their data showed that replication occurs in a conservative manner instead of semi-conservative. What fraction of the DNA helices will consist of mixed DNA after 4 rounds of replication in this case?

	None
	More than 75%
	25-50%
	51-75%
	Less than 25%

peachmarten804

Multiply questions here

Q2. What is the consequence of chromosome inversion on meiosis? (work on a zygote with one normal chromosome and one chromosome with an inversion)

Q3. Search the web or read the textbook. Find a disease that is caused by translocation. What kind of translocation causes the disease?

Q4. Briefly explain how downâs syndrome or other trisomy is generated (3 sentences should be enough for you to explain this clearly)

Q5. I mutated a culture of wild type E. coli cells and wanted to isolate mutants that are unable to synthesize uracil (a nitrogen base in RNA). How can I achieve my goal? (try to finish your answer in 2-3 sentences)

Q6. For the ura- mutant isolated in Q5, I want to convert it to URA+ by transformation. Please tell me how I can achive this transformation with 3 SIMPLE sentences

Q7. What is the difference and relationship between an Hfr cell and an F+ cell?

Q8. I want to set up a mating between an Hfr strain and an F- (ade- his- bio-) strain and detect bio+ recombinant. Please design the experiment for me. (What genotype for Hfr do you need to choose? How will you select your recombinant? etc).

Q9. I want to use phage T2 to transducer the wild type ADE2 gene from the wild type E. coli strain to an ade2- E. coli mutant. How can I do this experimentally? (please briefly describe the approach, not experimental details such as incubation for 10 min, etc).

Q10. We talked about recombination in both eukaryotes and prokaryotes. Are there any differences in these two recombination ? (what are they if there are?)

Q11. Whose (or what) experiment proves that DNA is the genetic material?

Q12. What knowledge did Watson and Crick use in constructing the DNA model?

Q13. How does the double helix model support the three major functions of genetic materials?

Q14. What is the major chemical force that holds DNA and histone together? Hydrogen bonds

Q15. If I label E. coli cells in an N15 medium overnight and chase cells in an N14 medium for 2 generations, what fraction of cells still carry the N15 label?

Q16. If a 1000 kilobase fragment of DNA has five evenly spaced replication origins and DNA polymerase moves at 1 kilobase per second, how many seconds will a cell take to produce two daughter molecules?

Q17. DNA polymerases catalyze the polymerization of nucleotides. Use the formula for enzyme catalyzed reaction (see the example) to describe DNA polymerases. Example: Enzyme Substrate A + substrate B -------------------ï product c + product D Q8. During DNA replication, what is the direction of the growing strand?

Q18. For DNA synthesis in cells, why are there a leading strand and a lagging strand?

Q19. The following is the DNA sequence of a template strand. If the primase begins to synthesize primers from the middle âgâ, what will the primer sequence be? (assuming the primer can be 8 nucleotides long) 5â GACTCTAgGACTCCT 3â

Q20. Both DNA polymerase I and DNA polymerase III synthesize DNA during DNA replication. Please state the different roles they played during DNA replication.

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Biochemistry 3382A Lecture Notes - Lecture 5: Plasmid, Conformational Change, Chromosome

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